m272 engine noise can anyone tell me what it is?
 

2006 e350
I looked at some other videos on youtube and there aren't any definite answers. people just suggesting many things that could be

I feel like its coming from the pass side head.

heres another video its hard to caprute since its not very evident at all times.


I don't think its anything to do with the block since it does not get louder on cold start. its exactly same regardless of engine temp

the air pump is very loud on startup though I don't know why or if its normal or not

Sounds like a lifter tick.

is that common? should i do anything about it? or is it ok to drive like this?

115000 got it with balance shaft codes fixed balance shaft and I belive the noise show up after I put everything back together. but I cant say for sure because I only drove it once to bring home and pulled the motor right away.
so Im not realy sure if it was there or not

That's a bad lifter

is it safe to drive like this?

is it lifter or cam gear?
can it be bad Camshaft Adjuster Magnet?

yes I did balance shaft oil pump both chains and all chain guides and tensioner

I installed the original cam sensors and magnets for now so new ones don't get any crap in them during the initial run
could one of the magnets be bad?

but I did follow the manual for whatever I found and I did use oem parts for everything


there are no codes. I scanned multiple times and only code was for driver side wheel sensor.
which im checking right now to see if its dirty or damaged.

it has good acceleration etc engine feels strong and noise doesn't seem to be affected by anything like temp or revs. it stays same volume and doesn't get louder or quieter under any conditions

I mean I cant really hear it when I rev up the motor so it either goes away or just blends in with the other noise but during idle it is constantly same noise cold or hot.


I am using 0w-40 mobil1 European from Walmart already
to be honest the engine is rather clean. I did not see any buildup looks like it was a healthy motor and car is excellent condition otherwise.

say I add one of those oil additives (whatever its called that's allover youtube now ) and noise goes away is that a sign of bad lifter for sure?

should I try simple zddp additive for now and see if it helps?

i got the magnets with the balance shaft kit
everything i got is oem i dont know if the ones that came with the car were oem or not but looks like they were.
and sensors as well and one extra filter.
will try to replace it
i didnt see any damage on cam lobes or cam gears
and i did install new timing plates? or whatever the disk that goes on the cam gears.

once i replace the magnets do i have to take it to dealer to recalibrate anything or the car does it automatically?

no I reused the old magnets for the break in period.just in case there are leftovers of any junk from the startup so it doesn't destroy new ones.

I reused spark plugs magnets and sensors for first few 100 miles. its been about 300 miles now I put new plugs in and about to replace the oil filter now and was thinking of just keeping the new ones until old ones go out. or just include them with the car when I sell

are the magnets calibrated each one individually or can I swap them around and see if something changes?

I mean would a bad magnet even cause that sound?

Ok I understand more now. Here is what I would do.

The cam adjuster magnets are known problems anyways and not expensive so order the kit with oil housing gasket and replace. Because you are pulling that off I would also bite the bullet and remove the cam covers and spin the engine at crank and inspect. No need to replace the cam sensors but change the o rings if you do or if oil is leaking. You aren’t throwing timing codes but you can check timing again here too. Make sure you apply gasket bead correctly and torque bolts at spec on cam covers.

Then report back.

well I did just finish putting everything together. I didn't see any damage on cam gear and used a pin when took it off and put it back.

I will start with replacing the magnet in question
how would I tell the valve tick vs piston sleeve bang?

Hello raverx3m,
I own a S350 with the M272 engine. I bought the car with a broken engine. I also replaced the balanceshaft, timing chain, chain tensioner, chain gliders etc. myself. I also found that my engine was clogged up with sludge and I about half of the hydraulic lifters were broken and replaced all of them. I reassembled the engine and torqued everything to spec. After driving for about 2000km without any problem yesterday I took the car to Germany and drove it at 200km/hr. No I am also experiencing the knock same as you do (did). I was wondering if you found a solution to the problem.

By the sounds of it it knocks once every engine rotation. If it would be a cam shaft timing issue I would expect all valves to make a noise that would be 8 times each rev. I intent to check the engine with a stethoscope today to see if I can pin point the location of the knock.

Please let me know if you found a solution.
Kind regards,
Frank

why is everyone calling them lifters? Lifters are on pushrod motors with cam in block. They are cam followers/buckets
Anyway, we have seen many 272 motors that are somewhat noisy like that, run fine and do not throw any codes? maintain oil level with proper oil and call it good, you could be chasing those noises for ever and tear into your motor only to find that upon re-assembly the noise persists?

my 2 cents

BTW, just curios how long can one drive with the lifters/cam followers noise before any problems develop? The "lifter" is just a piece of solid metal that the cam uses to push the valve stem, plus a hydraulic "spring" on the top of it, which follows the cam. Once the hydraulic part collapses (bad or dirty oil typically), the lifter becomes shorter and does not make a constant contact with the cam - the cam slams it only at the time of opening the valve - this is the noise we are hearing. So the stem and the cam will wear more, but since it's all lubricated I would expect that one can drive the car for tens of thousands of miles like that before any noticeable wear. Or am I missing something? Can the cam fail to fully open the valve for any reason?

I would assume that clogging up or destruction of plastic oil feed pipes like we had on the 1980s mercedes V8 is not a problem on the modern engines with a reasonable oil changes procedure?

Any deeper insight into the problem is appreciated, thanks! (Some people would say stop driving because you can destroy engine, others will say you can drive forever, I think both of those extremes are wrong - where is the middle truth?)

I would say that part of the cam follower/lifter problem is lack of lubrication along with the softer metal of the cam lobes versus the follower buckets. We have seen M156 motors with north of 180K miles that tick like crazy but still run fine and when the revs pick up you cant hear it anyway.
Long term effects would be that eventually the lobes become so worn that valve lift is reduced to the point of it affecting the combustion process, causing reduced performance/driveability and increasing hydrocarbons because of an inefficient mixture burn affecting the O2 sensors and tripping the MIL lamp. The other issue is the cam adjuster failure which will affect timing and and also throw a code because timing can be altered.

replaced cam adjusters didn't notice any difference...

had Mercedes tech listen to it he said its ost likely the main bearing... and that for a 2006 its normal first year production bs and I shouldn't worry about it...
but I find that a bit suspicious... a main bearing making noise that I shouldn't worry about

Hey raverx3m,

Did you ever get this figured out? I have pretty much the same sound on my son's E280 (3.0L M272 engine). I replaced all the cam followers since that's what a mechanic told me it was, but it didn't fix the problem (although a few of them were not in great shape). I'm thinking connecting rod bearings, but I won't be sure until the engine is out. I'm leaning towards finding a wreck and replacing the engine.

Here's a video of my engine:

Thanks,
Miles

Hi Miles,

My engine was burning oil because one of the cylinders had scoring in the cylinder wall. I decided to replace the lower block for a another used one. In the process I found two valve followers with a problem and replaced them. One had a squared roller and the other was missing the spring that holds it to the tappet. The noise is less now but not completely gone. I will keep driving it the way it is now.
While in there I checked for play on the rod bearings and did not find a problem there.
Hope this helps.

Regards Frank

My guess is that one/some of the hydraulic tappets are not performing as they should.
You can try oil additives to fix it (like I will do tomorrow) and if that doesn't work you can replace on/some hydraulic tappets.....or just leave it like it is.....it's just annoying...
I cannot find any documentation on how to replace the tappets on a M272....on some engines it's simple and you only need a simple special tool....on others you have to remove the camshafts.
BTW: I checked the timing chain and balance shaft yesterday and the are in great shape.....my SLK350 has 270K km on the clock and is running fine...only a light tick on driver side near firewall....I can live with that if it is too much hassle....but I want the old girl perfect!

Any thoughts on replacing the oil pump to address this? I have the same noise in an '11 E350 and I've seen multiple reports of people trying to replace the followers with no luck. I did see one comment in the video below saying he had remedied this issue in a number of cars by replacing the oil pump. Suffice to say it's a huge undertaking so I'm reluctant to try that based on one comment, but would gladly do so if that's the fix. The only other "fix" is to add an oil additive to thicken up the oil, but I would rather fix the actual issue.

I do need to scope my pistons to see how the walls look. I would think if it were a rod bearing it would knock more when you rev the engine, but it pretty much disappears with the slightest of revs.

I own 3 m272 engines. 178k, 82k, and 78k miles. The 178k and 82k motors sound like yours, I think it's normal. I haven't checked the 78k motor. These aren't quiet engines. My e55 and ML63 engines make plenty of noise at idle too.

+1

I think it sounds fine...

One of the videos [from another member] it clearly sounded like lifter tick. I haven't run into that issue on these motors, but on some inline 6 BMWs the lifters should get "sticky"/gum up and not fully expand with oil pressure. Usually due to some combination or using dino or long drain intervals, short trips, anything that caused excess deposits and varnish... Usually running a good synthetic like M1 0W-40 for a few short drains intervals (like 1000 miles or less) would clear it up. Also holding the RPMs elevated at say 2-3k would free them up as well.

Thanks for the responses. It gives me more reassurance about just leaving it be.

I'm sure you're right that it's normal and not worth worrying about, but man that noise is embarrassing. It sounds like rod knock (though I know it's not). It'll make selling it more difficult once the time comes too.

I've been changing the oil with M1 twice a year for two and a half years at this point so I've given up hope that something sticky just needs to be freed up. I only put on a few thousand miles between oil changes. :nix: I tried Liqui-Moly Pro-Line Engine Flush right after I bought it hoping that would help with no result, too.